Aerosol dispenser with sponge follower and method of making same



June 15, 1965 w. H. KIBBEL, JR., ETAL ,2

AEROSOL DISPENSER WITH SPONGE FOLLOWER AND METHOD OF MAKING SAME Filed Jan. 16, 1965 [Mk/W Way/w ff I058 5 11/1455 E. 41263-55 BY 27M A M x/M ram/ifs United States Patent 3,189,231 AEROSOL DISPENSER WITH SPONGE FQLLOWER AND METHOD Uh MAKING SAME William H. Kibbel, Jr., and James E. Kressbach, Pennington, N.J., assignors to FMC Corporation, New York,

N.Y., a corporation of Delaware Filed Jan. 16, 1963, Ser. No. 251,790

5 Claims. (til. 222-489) This invention relates to pressurized dispensers, and particularly to pressurized dispensers which may be filled with product to be dispensed and pressurizing medium at ambient pressures and temperatures, and which Will not corrode and thereby fail in storage and use.

Foodstuffs, cosmetics, insecticides and other consumer products have been packaged in pressurized dispensers, most frequently in systems in which a gas dispersed in and above the product upon demand provides a pressure which forces the product and gas through an orifice in the dispenser. Another system which has been employed to provide the dispensing pressure locates the gas above and in contact with the product to be dispensed. In these systems the product may be forced through an orifice by way of a tube which dips into it, or may communicate directly with a valve.

These systems of dispensing have been suitable for many uses. However, some products are deleteriously effected by the pressurizing gas, and therefore do not lend themselves to admixture or even contact with gases. Furthermore, the gas in such systems tends to be; wastefully discharged, with the result that often a substantial amount of the product remains in the dispenser after the gas has dissipated. Likewise, loading of the dispenser with the product and dispensing gas has been difficult, requiring either careful pressure or temperature control.

A new type of dispenser has been developed, which provides for separation of the pressurizing gas from the product to be dispensed. The two are separated by a piston, which is forced against the product by pressure of the gas. The product in turn is released on demand through an orifice in the chamber of the container in which it is held. a

This new system is very useful, largely avoiding the problem of admixture of the gas with the product, and making it possible todispense essentially all of the prodnot; that is, the gas does not have access to the orifice, and therefore will not bewastefully discharged. Furthermore, since the gas is not mixed with the product, foaming and other product modifications are avoided.

The preferred method for introducing the gaseous pressurizing means into the pressure chamber of such new dispensers is to introduce hydrogen peroxide in an aqueous solution containing a hydrogen peroxide-decomposing agent such as ferrous ammonium sulfate. This solution remains in liquid condition for a sufficient time to permit the container to be filled conveniently and capped, and thereafter decomposes to provide oxygen gas for pressurization along with a small volume of water.

This system has been highly useful. However, it has been found that the pressurizing oxygen gas derived from the hydrogen peroxide creates an oxygen concentration difference across the portion of the metallic container wall separating the product to be dispensed from the gas; this causes corrosion of the container by an oxygen concentration cell mechanism. Furthermore, when the container is damaged leakage of gas past the piston may occur, and one of the principal advantages of the system is lost.

It therefore has been desired to provide a pressurization system which would have the advantages of the piston dispenser system employing hydrogen peroxide-introduced pressurization, and yet which would avoid the harmful corrosion of containers encountered when the Ice preferred hydrogen peroxide gas-generation system is employed. It has also been desired to employ such a system which would not permit the pressurization gas to penetrate past the piston into the product section of the container, as is apt to happen when the gas is not contained in a system of its own.

It has now been found that the above desirable ends can be accomplished by providing in a container having a space for product to be dispensed and a valve communicating with this space for controlled discharge of the product, a pressurization and piston unit positioned to force the product toward the valve and comprising a sealed outer bag of resilient, gas-containing material having the general shape of the insideof the container and having a diameter about that of the container, and having within it a resilient foam body of a shape and size to press the bag into contact with the inside of the con-' tainer and, on the side of the foam body away from the product to be dispensed, a gas having a sufficient volume and pressure to inflate the bag and cause the latter to press the product on demand out of the container through the valve. The pressurizing gas within the bag is provided by decomposition of a solid or liquid which can be introduced into the bag and sealed therein, and which remains in its solid or liquid form for a sufficient time to permit positioning of the bag, and also the product to be dispensed, into the container, and to permit the container to be capped with a valve. Typical liquids for use in such a system will include aqueous hydrogen peroxide solutions containing a decomposition agent such .as

catalase, ferrous ammonium sulfate, and the like. Useful other gas-producing materials include carbonates and bicarbonates which react with acid to liberate CO gas,

lithium hydride which generates gas on contact with water, solid carbon dioxide, and the like.

It is apparent that the pressurizing gas in the pressurization and piston unit is not accessible to the product to be dispensed. It is sealed in the unit and can not bypass the piston, as may happen where the piston and pressurization means are not integral, and mix with the product either foaming it or causing other undesirable effects. Likewise, the gas employed for pressurization can not come into contact with the container wall where it may cause corrosion, and it is now possible to provide foodstuffs and other pasty and syrupy products. This.

container has a chamber 12 for housing the product 14 to be dispensed, and a pressurization and piston unit 16 composed of a resilient flexible bag 18, an open-celled foam body 29 and a space within the bag for pressurizabeen dispensed, and exerts an equalizing pressure on unit tion gas 22. The foam body may be provided with a gas-imprevious face 24 at its upper end, and with gasimprevious sidewall 26; the bottom 28 mustbe permeable to gas. In the showing of FIG. 1 the product has not 16, restraining that unit against expanding within container 10.

The container is equipped with a dispensing valve 30 normally closed and adapted to be opened to permit controlled release of product 14. The valve may be of any Patented June 15, 1965 type desired, and in the case illustrated is a tube 32, mounted in a rubber eyelet 34 in the cap 36, and having a central passage 38 communicating with a number of radial grooves 44 in the upper side of head portion 42 of the valve. Separate pins 44 connect head 42 with tube 32 such that when the tube is rocked against the outward pressure exerted by helical spring 46, product 14 in the container under pressure will be dispensed through passage 38 and 40.

As shown in FIG. 2, after dispensing of a part of product 14, the bag 18 containing the foam body it and the residual liquid from gas-generating liquid and gas 22 is partially expanded to fill the void created by this removal of product. The upper face 24 of the bag 13 contacts product 14 forcing it upward against the valve, which in turn is actuatable to release product through tube 32. In the dispensing operation, the bag and piston, properly sized, move integrally within the container.

The container is filled from the top in order of pressurization and piston unit 16, which contains at this stage liquid hydrogen peroxide or other system which generates gas upon standing, followed by product to be dispensed. At this stage and for a time dependent upon the pressurization system employed, for example about an hour to several Weeks, the container is not under pressure and accordingly can be handled at ambient pressure and temperature conditions. Upon standing, for the predetermined time, the hydrogen peroxide or other gas-generating system in the bag undergoes decomposition and forms oxygen or other gas 22 which expands the bag and exerts a pressure through foam body 29 to the top of bag 18 which in turn forces the bag upward against product 14.

The pressurizing gas in the bag 1?, has no communication with the product or with the valve, and therefore is not lost directly to the atmosphere or mixed with product 14, so that pressure continues to be exerted on the product which can be completely discharged from the container. The valve may be at any point in the container which assures complete product dispensing, it being necessary only that there be communication between the product to be dispensed and the valve.

In order to avoid substantial leakage of the gas from the pressurization and piston unit, the bag normally is formed of a substantially gas impervious film having a thickness of about 0.0005 inch to 0.005 inch, such as Teflon, plasticized polyvinyl chloride, polyethylene, polychlorofluoroethylene, polyvinylidene chloride and the like, which is sufiiciently impervious to the pressurizing gas so that deleterious amounts of such gas do not penetrate the film. These flexible films are collapsed after introduction of the foam body and gas-generating liquid and prior to scaling of the bag to permit their being crinkled up for insertion into the container. The bag may be heat or adhesive sealed, and the like, by well-known means.

The bag is shaped to conform to the shape of the container, which preferably is cylindrical, and is sealed at both ends following introduction of the foam body and the liquid which is to decompose and form the pressurizing gas. The bag is collapsed prior to being sealed, in order to displace air within the bag and permit introduction of the full charge of product into the container. The outside diameter of the bag is essentially equal to, and of the foam body is slightly larger than, the inside diameter of the con tainer, so that the bag and its contained foam body fit snugly against the walls of the container. This guards against leakage of the product to be dispensed past the bag with consequent wasting of the product, which can not be dispensed through the valve from beneath the bag if it reaches that position. The preferred shape for the foam body is that of the container, although an advantageous shape for this element is a sphere which can not tilt or otherwise be displaced in the container. In either case, the foam body serves to position the bag properly (it within the container, avoiding tilting of the bag, entrapment of product, and the like.

The height of the foam body relative to its diameter should be no less than about 0.5 to 1, and normally is not greater than about 1 to 1. If this ratio is substantially less than 0.5 to 1, the foam body tends to tilt within the container, with the result that it Will not serve as a piston. However, it is possible to employ such elements having smaller or larger height to diameter relationships where desired. The bag has a height sutficient to expand to a point where it discharges all product from the container.

The foam body preferably is formed of a polyurethane foam having intercornmunicating cells, although opencelled and resilient vinyl, rubber and other foams may be employed. Furthermore the foam may have cells which do not interconnect provided they will rupture, for example, upon being compressed by the gas when it is generated or for inserting in the container thereby creating connections between the cells.

The top and preferably also the side of the foam preferably are rendered impervious to cause the foam body in use to be forced against the upper end of the bag so that the foam together with the upper bag end serves as a piston. If the cells are open and the top of the foam body is not sealed, the gas upon equalizing in pressure on both sides of the foam may leave a gas space above the foam body within the bag; this is not critical, as the bag itself will then inflate and push product toward the valve, but this will not serve as well as the shaped foam body in forcing all product from the container.

The preferred gas-providing system for use in the present pressurized dispenser is aqueous hydrogen peroxide containing a material which is catalytic to its decomposition. The hydrogen peroxide most suitable is employed in aqueous solution, for example as the commercially available aqueous 35% hydrogen peroxide or as aqueous hydrogen peroxide at any other higher or lower concentration. It is important only that the final solution contain an amount of hydrogen peroxide which generates the amount of oxygen gas required for adequate pressurization throughout the dispensing of all of the product. Whatever gas-generating system is employed it is important that the gas not be generated in a pressurizing amount until the container is filled and sealed. This time is from 15 minutes to several days after preparation of the gas generating system, and selection of a gas source is made with the particular time requirements in mind.

Whereas in systems in which a hydrogen peroxide solution is used and is in contact with the container the hydrogen peroxide solution stabilizers and corrosion inhibitors such as phosphates, alkaline materials and the like must be used, this is not necessary in the present device, in which the hydrogen peroxide solution and the gas therefrom does not contact the container walls. The preferred catalyst for decomposition of the hydrogen peroxide to provide oxygen gas is ferrous ammonium sulfate, although other catalysts for decomposition of hydrogen peroxide such as ferric chloride, yeast, catalase, copper salts such as copper sulfate, copper chloride, copper nitrate, or other typical catalysts may be employed. Improved control of decomposition rate can be effected by addition of decomposition retarders such as phosphates, silicates and other known inhibitors.

Other gas generating systems such as aqueous solutions of carbonates, bicarbonates, nitrates and the like will generate gas upon reaction with an acid. Likewise, agents such as lithium hydride liberate gas upon contact with water and solids such as frozen carbon dioxide sublime to yield carbon dioxide gas. It is important only that a system be employed which does not generate a pressurizing amount of gas until after the container is filled and capped.

The gas-generatin g material is used in an amount which upon decomposition provides a pressure suitable to the particular container and product to be dispensed, preferably 20 to 110 p.s.i.g. in the container initially, and provides a sufficient volume of gas to exert a dispensing pressure on the product to be dispensed near the end of the dispensing operation. A typical cylindrical dispensing container has a volume in the absence of product to be dispensed of 13.5 cubic inches, and measures 4 inches high by 2 inches in diameter. When product in the amount to occupy about 7 cubic inches is present in such a container, a typical pressurizing system of the herein type occupies about 6.5 cubic inches, and about 0.35 to 1.99 grams of hydrogen peroxide on a 100% basis provides suflicient gas to create a pressure in the container of 20 to 110 p.s.i.g. over a period of several hours for several days depending on the decomposition catalyst used.

The amount of hydrogen peroxide required to provide a given pressure can be calculated readily, the volume of oxygen gas being provided by decomposition of a given amount of hydrogen peroxide being well known. Thus 1 cc. of 27.5 weight percent hydrogen peroxide yields 100 cc. of oxygen gas, while 1 cc. of 35 weight percent hydrogen peroxide yields 130 cc. of oxygen gas and 1 cc. of 50 weight percent hydrogen peroxide yields 197 cc. of oxygen. The amount liberated by other hydrogen peroxide solutions and other gas generating solutions can be calculated readily. Volumes referred to are measured at standard conditions, C. and 760 mm. Hg pressure.

The container can be formed of any suitable material which will withstand the pressure of the gas in it. The pressure is at its highest point after decomposition of the gas generating system and before dispensing of any product, and normally is about 100 p.s.i.g. Pressures as low as 20 p.s.i.g., and as high as 110 p.s.i.g., may be employed. Selection of a suitable pressure depends largely upon construction of the container and the nature of the product being dispensed, with pasty products requiring a greater pressure for dispensing than is required with low viscosity liquid products.

Normally the container is constructed of a metal such as steel or aluminum. Preferably it is coated with a cor-- rosion resistant material such as tin, a phenol formaldehyde resin, an epoxy resin, an alkyl resin, a vinyl resin or the like although the corrosion resistance of the con tainer is not as important a consideration as in cases where the pressurizing means is in direct contact with the container. In the present dispenser, the principal concern is with the product to be dispensed which contacts the container.

The following examples are given only by way of illustration of the present invention, and are not to be considered to limit the scope of the invention.

Example 1 An open cell polyurethane foam piston measuring 2.066 inches in diameter was placed in a polyethylene tubing .002 inch thick with a lay flat diameter of 3% inches and a length of 7 inches. One end of the tube was heat sealed to form an effective closure. Into this assem bly was placed 5.0 ml. of the H 0 solution and 0.2 ml. of the ferrous ammonium sulfate catalyst solution described below. Air was squeezed from the section of the bag between the open end and the piston by folding the bag fiat onto the piston and the open bag end heat sealed. The assembly was compressed and then inserted into a 6 ounce, 4 pound tin cylindrical steel can coated on its interior surface with a phenol formaldehyde lacquer, through the 1 inch opening in the top. The can was 2 inches in diameter and had a volume of 13.5 cubic inches. This operation was conducted at a temperature of 72 to 75 F. Within 4 minutes after the introduction of this bag-piston unit, 157 grams of a grape jelly was placed on top of the unit, and the top of the can was capped with a cover containing a valve. The pressurizing solutions were as follows:

SOLUTION 1 (USED IN AMOUNT OF 5 ML.)

These solutions were mixed to provide a pressurizing solution having a pH of 6.05 and containing 140 ppm. ferrous iron. The pressure of the gas in the container after decomposition of the hydrogen peroxide in 14 days was p.s.i.g. Essentially all of the grape jelly was dispensed from the container after storage thereof for 6 weeks without any corrosion being observable on the inside of the container.

Example 2 A dispensing can was prepared as in Example 1 and filled with grape jelly. In this case, the can was intentionally dented to simulate mishandling in use. Full product delivery was realized and again no corrosion of the cans interior could be observed after 6 Weeks storage.

Example 3 When a side seamed container was used in place of the container of Examples 1 and 2 and a .0015 inch thick polyvinylidcne chloride bag used in place of the polyethylene bag of those examples, essentially full product discharge was achieved with no corrosion after 6 weeks storage.

Pursuant to the requirements of the patent statutes, the principle of this invention has been explained and exemplitied in a manner so that it can be readily practiced by those skilled in the art, such exemplification including what is considered to represent the best embodiment of the invention. However it should be clearly understood that, within the scope of the appended claims the invention may be practiced by those skilled in the art, and having the benefit of this disclosure, otherwise than as specifically described and exemplified herein.

We claim:

ll. A pressurized dispenser comprising a container, product to be dispensed, a valve communicating with said product for controlled dispensing thereof and a pressurizing system for exerting pressure on said product to be dispensed through said valve upon opening thereof, in which there is provided as said pressurizing system a pressurization and piston unit having a sealed outer bag of resilient gas containing material having the general diameter of the inside of said container, and within said bag a resilient foam body of a shape and size to press the bag into contact with the inside of said container, and on the side of the foam body away from the product to be dispensed a gas in an amount sutficient to inflate said bag and to create a dispensing pressure on said product through said body and said bag.

2. Pressurized dispenser of claim 1 in which the container and bag are cylindrical in shape.

3. Pressurization and piston unit for use in providing dispensing pressure in a dispenser system composed of a valved container, product to be dispensed and a pressurization unit, comprising a sealed outer bag of resilient gas-containing material having the diameter of the inside of said container and having therewithin a resilient foam body of a shape and size to press the bag into contact with the inside of said container, and on the side of the 7 foam body away from the product to be dispensed, a gas in an amount sufficient to inflate said bag and to create a dispensing pressure on said product through said body and said bag.

4. Pressurized dispenser of claim 3 in which the bag and foam body are cylindrical in shape.

5. In the filling of a pressurized dispenser by introducing, into a container a pressurizing system, product to be dispensed and a valve adapted to seal the container and to pass product on demand, the steps which comprise providing an open bag of resilient material having the general diameter of the inside of said container, introducing into said bag a foam body of a shape and size to press the bag into contact with the inside of said container and a gas-generating system in an amount which Will provide a pressurizing amount of gas, collapsing said bag to dispel air, sealing said bag, inserting the collapsed bag and product into said container, sealing said container and permitting said gas-generating system to generate pressuri ing gas.

Reterences Cited by the Examiner UNITED STATES PATENTS 1,235,550 8/17 Carmody 222-3865 2,798,639 7/57 Urban 222-3865 X 2,809,774 10/57 Kaye et al. 222-387 X 2,815,152 12/57 Mills 222-386 2,890,652 6/59 Iauch et al.

3,022,923 2/62 Hoffman 222-387 3,117,404 1/64 Miles.

3,117,699 1/64 Epstein 222-389 3,128,922 4/64 Kuster 222-389 FOREIGN PATENTS 1,046,624 7/53 France.

EVERETT V. KIRBY, Primary Examiner. 

1. A PRESSURIZED DISPENSER COMPRISING A CONTAINER, PREDUCT TO BE DISPENSED, A VALVE COMMUNICATION WITH SAID PRODUCT FOR CONTROLLED DISPENSING THEREOF AND A PRESSURIZING SYSTEM FOR EXERTING PRESSURE ON SAID PRODUCT TO BE DISPENSED THROUGH SAID VALVE UPON OPENING THEREOF, IN WHICH THERE IS PROVIDED AS SAID PRESSURIZING SYSTEM A PRESSURIZATION AND PISTON UNIT HAVING A SEALED OUTER BAG OF RESILIENT GAS-CONTAINING MATERIAL HAVING THE GENERAL DIAMETER OF THE INSIDE OF SAID CONTAINER, AND WITHIN SAID BAG A RESILIENT FOAM BODY OF A SHAPE AND SIZE TO PRESS THE BAG INTO CONTACT WITH THE INSIDE OF SAID CONTAINER, AND ON THE SIDE OF THE FOAM BODY AWAY FROM THE PRODUCT TO THE DISPENSED A GAS IN AN AMOUNT SUFFICIENT TO INFLATE SAID BAG AND TO CREATE A DISPENSING PRESSURE ON SAID PRODUCT THROUGH SAID BODY AND SAID BAG. 